Adult BMI calculator
Enter your height and weight to see your BMI and a reference weight category for adults aged 20 and over. Choose metric or imperial units, then read the result as an initial screening measure.
Enter measurements to calculate BMI
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BMI history
Calculate and read BMI in 3 steps
Choose metric or imperial
Metric uses centimeters and kilograms; imperial uses feet, inches and pounds. Use one system for both measurements.
Enter height and weight
Check the units, then select Calculate BMI. A name is optional and only identifies the result in browser history.
Review BMI and reference category
The result uses screening categories for adults aged 20 and over. The weight range follows BMI 18.5 to less than 25; it is not a personal target.
How to calculate BMI from height and weight
BMI = weight (kg) ÷ height (m)². Convert 175 cm to 1.75 m first: 70 ÷ (1.75 × 1.75) ≈ 22.9. In the tool, enter 175 in the cm field and 70 in the kg field. For feet, inches and pounds, choose Imperial so the tool converts the units.
The reference weight range multiplies each BMI threshold by height (m)². Enter your own height and check the weight range in your selected unit; the range changes with height.
What is a normal BMI for adults?
For adults aged 20 and over, the tool uses the same reference BMI ranges for men and women. Compare your number with the table, then read the limits below; a BMI category alone cannot establish a person’s health.
| BMI | Result category | How to read it |
|---|---|---|
| <18.5 | Underweight | Discuss concerns about weight or health with a health professional. |
| 18.5–<25 | Within reference range | This number does not directly measure body fat or overall health. |
| 25–<30 | Above reference range | Consider other health factors for an individual assessment. |
| ≥30 | BMI 30 or above | This is a screening category, not a diagnosis from one calculation. |
Check these thresholds against CDC adult BMI categories.
Limits of BMI for assessing health
BMI is a screening measure, not a direct body-fat measurement or a diagnosis. People under 20 need age- and sex-based interpretation; during pregnancy or with high muscle mass, discuss the result with a health professional instead of setting a weight goal from this table.
Health risk may rise at lower BMI values in some Asian populations, but there is no single new set of cutoffs for every Asian population. This page uses the international categories above.
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